Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < g[u].size() ; i++ ) ~~^~~~~~~~~~~~~ user.cpp:22:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0 ; i < g[u].size() && v2[g[u][i]] == 1 ; i++ ); ~~^~~~~~~~~~~~~ user.cpp:24:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i == g[u].size()) ~~^~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:34:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", &n, &m ) ; ^ user.cpp:36:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin, "%d%d", &u, &u2); ^